Question

A football is punted into the air. Its height, h, in metres, after t seconds is given by h(t)=1+24.5t-4.9t^2
a) Find the maximum height of the ball
b) When does the ball reach its maximum height?

Answer 1

is this flvs

Answer 2

you can find the maximum height by converting the equation to vertex form or by using calculus

Answer 3

@DaBest21 no

Answer 4

@welshfella do i have to complete the square?

Answer 5

yes

Answer 6

h(t)=1+24.5t-4.9t^2
= -4.9(t^2 - 5t) + 1
= -4.9[(t - 2.5)^2 - 2.5^2] + 1

Answer 7

maximum height is when t = 2.5
h(2.5) = -4.9 * -6.25 + 1

Answer 8

time to reach maxm height is 2.5 seconds
maxm height = -4.9*-6.25 + 1

Answer 9

ok?

Answer 10

@welshfella how did you get 2.5 seconds?

Answer 11

Shelby, have you been studying calculus, or is this problem from an algebra course?

Answer 12

5 /2 = 2.5
- completing the square

Answer 13

@mathmale no i'm not studying calculus. I'm taking Functions but this question is based on quadratics

Answer 14

i'll leave you in capable hands of Mathmale

Answer 15

OK, then your welshfella is correct in seeking the vertex of the curve by completing the square. However, there are other ways to do that. You could re-write the equation in the form ax^2+bx+c and then find the x-coordinate of the vertex by calculating -b/2a.

Answer 16

That is, t=-b/2a. This t value represents the number of seconds it took the ball to reach its max height.

Answer 17

alright, i'll try writing this out.
one sec

Answer 18

Given h(t)=1+24.5t-4.9t^2, identify the coefficient of the t^2 term. This is "a." Then identify the coeff. of the t term. This is "b"